Many substances require heating for proper use and often the heating must be to a controlled temperature. Poaching or boiling with water is a most common controlled method of heating because of the specific temperature at which water boils prior to vaporization (100° C., 212° F.). However, in order to control heating temperatures (i.e. maintenance of temperatures at specified levels) at other than the water boiling temperature, heating devices are used, invariably with thermostatic controls which turn the heat on and off to maintain a constant temperature. Electric and gas heaters are most often provided with thermostats which control the current and valve flow respectively, to control heat intensity and thus maintain a pre-determined temperature. With sources of heat such as candles and the like, thermostatic control of the heat intensity and thus temperature control is not a readily viable option.
An example of candle heat application requiring at least a modicum of temperature control is that of heating substances for aroma generation such as waxes with fragrance components which are released only with heat. Excessive heating may be detrimental (with excessive aroma generation) but no appropriate temperature control is commonly used or even commonly known.
Waxes, for their various utilities, require heated melting. Waxes are solidified viscous, usually burnable materials (e.g., paraffin, fats and hydrogenated oils such as soy wax) which have historically been used for illumination as taper candles. At present, more commonly, the waxes, with fragrance additives, are used for providing a pleasing or masking ambient aroma (aromatherapy). The wax is used in candles or as non-candle pellets, blocks or as glass container fillings, heated by a secondary source of heat, to release the aroma.
Another common use of ingredients found in waxes, is ambient temperature skin treatment such as soaps, lotions and the like, most often with a soy oil component. Lotions, in liquid form, however generally can only contain relatively minor amounts of soy derivatives and complexes in liquid carriers.
Some actual waxes are however used at higher temperatures, at which they are melted and used for skin application in heated form such as paraffin dips. Depilatory waxes are also often warmed prior to use. Care must however be taken with such applications to constantly maintain temperature control since overheating will detrimentally scald the user's skin. These waxes are heated and melted either in thermostatically controlled devices or are heated to the point of melting and the heat source is removed. With the latter embodiment, the wax must be quickly utilized before it re-solidifies. Paraffin baths must be kept at a very narrow low heat range (123° F. to 129° F.) because of full limb immersion with little heat loss.
Melted soy wax of some soy based candles has been touted as being beneficial for skin application. The melted soy wax (sometimes with other skin beneficial ingredients) is taken from pools of the melted soy wax surrounding the candle wick, after the candle has been extinguished, and before the heated candle material has had a chance to cool and solidify, i.e., a short window of possible use without continued heating (unless the candle is re-lit). Additionally, much of the candle wax available for skin application may be lost by fuel consumption if the candle is allowed to continue burning.
Non-candle waxes used in aromatherapy are usually small pellets or larger blocks without wicks which are heated with candle warmers. These candle warmers are generally comprised of hollow or open ceramic or glass containers or stands with an upper dished portion for placement of the pellets or blocks of the aromatherapy wax. Commonly, a tea light candle is placed within the container or below the dished portion for providing the heat for melting the wax and releasing the fragrance. Over time (often within thirty minutes) the wax melts and puddles within the dished portion and, despite extensive ventilation of the container with vent apertures, the wax may reach temperatures of 250° F. and above since temperature control of candle generated heat is not readily feasible. At such temperatures, the container cannot be readily handled except with heat insulated materials and the released fragrance can become excessive, overpowering and even toxic. Alternatively, electric heaters, without temperature control, akin to coffee cup warmers, are utilized to provide the requisite heating. Again, this may lead to excessive heating levels (or inadequate heating and utility) As referred to above, waxes used for skin treatment or skin therapy include melted paraffin dips or baths wherein a user dips a hand, foot or other body part therein with the wax hardening upon removal of the body part from the bath and the hardened wax is removed by being peeling off. The bath is almost always an electric device with a thermostatic control (a temperature sensitive element which controls the heat reaching the contents) to ensure that the paraffin does not overheat and scald the user. The paraffin itself however, has little particularly significant beneficial effect on the skin except for the effect of the imparted heat or warmth since it is not skin absorbable and is only a skin surface treatment. Since it is organic and non soluble, paraffin is also difficult to remove from skin and fabrics. A recent paraffin wax treatment eschews electrical heating (or heating with a microwave) and utilizes an exothermic reaction with water to heat the paraffin to the desired temperature of 122° F. and maintaining it by insulation in a sealed glove or slipper.
Soy derivatives and waxes on the other hand have been found to be beneficial to skin, with lotions of soy complexes being absorbed into the skin with improvement in the appearance of skin tone, softening and smoothing skin texture, and moisturizing dry skin areas. In addition, soy based waxes are water soluble and are easy to remove by simple washing. Various manufacturers have therefore formulated lines of soy based non-wax lotions for use in skin care. Such lotions are however used at ambient temperatures with relatively minimal soy oil content and do not have the added benefit of being applied to pores opened with heat. To take advantage of the benefit of heated soy wax as a skin application, soy based wax candles have been marketed specifically, as described above, for the application of soy containing wax at elevated temperatures. With such candles the users are instructed to extinguish the flame after the soy wax has melted and to use the melted material for topical skin application. However, there remains the constant danger that the user will not extinguish the flame and will be burned. In addition, the topical application and use is within a short window of time before the soy based wax re-solidifies. The candle wax also objectionably retains a burnt aroma from having initially been used as a candle fuel.
In any event, the most disadvantageous feature of such candles is the inclusion of combustion enhancing skin adverse additives. Soy oil or wax in itself has an unpleasant odor making it unsuitable for skin application without the further inclusion of masking fragrances. However, many normal fragrances used with the soy based lotions are unsuitable for candle use since they impede proper candle burning. Furthermore, many fragrances which do support a properly burning candle flame are not acceptable under FDA and IFRA standards for skin application, either in any amount or in the amounts used in candles, and any benefit achieved by heating the soy based material is lost by toxicity engendered by the necessarily added unapproved fragrances. Examples of fragrances suitable for candles include IFF fragrance designated Juicy Orange which is only recommended for candle use and not skin lotion use. IFF Zesty Grapefruit fragrance is recommended for both candle and lotion use but with the former at levels of 3-6% whereas for the latter, the maximum is 3%. At present, wax heating of skin suitable waxes is via candle wax residue, as described, or by means of electrical thermostatic controlled heaters such as used for paraffin baths.